Sewing-machine tension.



S. A. DAVIS. SEWING MACHINE TENSION. APPLICATION FILED MAR.29, 1909. 1,014,050, y Patented Jan. 9, 1912.

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STEPHEN A. DAVIS, OF NEWARK, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO DOMESTIC SEWING MACHINE COMPANY, A CORPORATION 0F MAINE.

SEWING-MACHINE TENSION.

To all whom t may concern:

Be it known that I, STErnnN A. Davis, of No. 154: Roseville avenue, in the city of Newark, county of Essex, and State of New- Jersey, have made a certain new and useful Improvement in Sewing-Machine Tensions, of which the following is a specification.

My invention relates to sewing machines, and particularly to tensions for use on such machines.

Among its objects are the provision of a simple form of tensioning device which shall be efficient in its operation and which shall be of neat and pleasing appearance, in which the tendency of the thread to wear a groove in the tensioning surfaces shall be obviated, wherein the means for releasing the tension shall serve also as a means for preventing the thread from being'accidentally removed from the tensioning device and in which simple and efficient means may be used for increasing or decreasing the tension and which shall not be exposed to accidental derangement.

Other objects of the invent-ion will appear in the course of the following description.

With the above and related objects in view, my invention consists of the parts, improvements and combinations hereinafter set forth and claimed.

In the drawings annexed hereto and forming a part of this specification, Figure 1 is a view in side elevation of a tension embodying my improvements, the same being shown applied to a machine head shown in dotted lines; Fig. 2 is a vertical, central longitudinal, cross-sectional view of the tension shown in Fig. 1; Fig. 3 is a view similar to Fig. 2, but taken at right angles thereto; Fig. l is a side elevational view, and Fig. 5 is a cross-sectional view of a detail of construction.

Reference numeral 1 indicates the barrel or casing of my improved tensionfwhich is secured to the machine head 2 in any convenient fashion, a desirable form of securing means for this purpose being provided by lugs 3 and screws f1 which pass through openings in the lugs and are secured to the machine head, upwardly extending projections 5 being provided for the reception of the holding screws, and a space 5 being left between the barrel 1 and the machine head and between the projections 5. The

barrel 1 is provided with a semicircular slot j Specification of Letters Patent.

Application filed March 29, 1909.

Patented J an. 9, 1912.

Serial No. 486,491.

6 terminating in a circular opening 7 which passes centrally and longitudinally through the barrel and preferably near the upper end thereof and through which the thread is passed when the machine is operated. The barrel 1 is closed at its upper end except for a central opening 8 through which is inserted the device for releasing the tension and for retaining the-thread from accident-al disengagement which will be hereinafter described. The barrel 1 is preferably circular in cross-section, but it is to be understood that other cross-sectional forms may be used within the spirit of my invention. The tensioning surfaces are provided by disks 9 and 10 placed within the barrel 1 and between the adjacent faces of which the thread is passed.

A spring 11, here shown as a spiral spring, but which may be of any other equivalent form, is provided in order to hold the tension disks in contact and to frictionally retard the thread in its progress through the device in order to give it the desired tension. Any convenient form of adjusting means for regulating the pressure of the spring 11 upon the tension disks may be used, but the form of adjusting device which I consider preferable comprises a screw 12 which fits loosely within an opening 13 in the machine head in line with the axis of the barrel 1 and is provided with a longitudinal slot or groove 14k. A pin 15 is inserted in an opening provided for that purpose in the machine head and its end enters the slot 13 thereby preventing the rotation of screw 12. Screw 12 is provided with a large flat head 16 upon which the spring 11 rests. Before being placed in position within the machine head, the screw 12 is screwed through a screw threaded opening in a knurled disk l17 which fits loosely between the machine head and the base of the barrel 1 as shown ,clearly in Figs. 1 and 2., This knurled disk 17 is protected from eing rotated accidentally by being placed below the other parts of the tension so that in order to rotate it readily it is necessary to place the thumb on one side and the iinger on the other, the space between the thumb and linger of the operator straddling the barrel of the device, as will be understood. Rotation of the knurled disk 17 in one direction raises the head of the screw 12 and increases the pressure between the disks 9 and 10,

while rotation in the opposite direction decreases the pressure. provided with ra central aperture and the lower disk 10 is provided with a recess in alinement with the aperture in the upper disk. If desired, this recess may be formed by making an aperture entirely through the lower disk, as shown at 25 in F ig. 5. This aperture is screw-threaded, and afscrew 26 with a fiat end is screwed tightly into place therein and extending partway there through, its head preferably being allowed to extend below the disk. In this way, the depth of the recess about the screw can be readily regulated by adjustment of the screw and the recess can readily be provided with a flat bottom which is diilieult lto attain by drilling or otherwise forming the -recess directly in the disk.

A push button 18 is provided which passes through the opening 8 in the top of t-he barrel and which has a portion 19 of reduced diameter passing through the opening within the disk 9 and entering the recess in disk 10. This portion of reduced diameter is somewhat longer than the combined depth of t-he opening in disk 9 and the recess in disk 10 so that its depression will cause the latter disk to move downward away from disk 9 thus releasing the thread from pressure between the two disks. It also has a transverse slot 20 cut in it-s end and the front half is shortened and provided with a cam shaped surface 22 as is clearly shown in Fig. 3. A pin 23 passes through an opening in the side of the barrel 1 and enters a slot in the side of the push button 18 so as to prevent the rotation thereof. The said' slot does not extend quite to the lower edge of the larger portion of the push button shank so that to entirely remove the push button the pin 23 must iirst be withdrawn slightly. The head of the push button 18 is normally situated slightly above the top of the barrel so as to allow for depression o-f the same when it is desired to relieve the pressure.

The operation of a tensioning device constructed in accordance with my invention is as follows: Vlien the device has been assembled, as above set forth, the slot 6 facing the front of the machine head, the thread is introduced by pushing it back within the slot until it contacts with the cam shapedl surface 22 at the bottom of the push button 18. On the thread being pushed still farther back, the push button 18 is raised, and the thread enters the slot 2O in the push button which immediately7 drops into place and prevents the thread from being accidentally removed. In order to remove the thread from the tension, it is necessary to raise the button 18 to release it. If it is desired to release the tension upon the thread so that the same may be pulled longitudinally there- The upper disk 9 isy thro-ugh, the push button 18 is depressed by the hand thus compressing the spring 11 and separating the disks 9 and 10, so that the thread may pass through without being squeezed or pressed between these disks. As the aperture in the disk 9 and the recess in the upper face of the disk 10 are centrally arranged therein, it is evident that these disks which lit loosely within the barrel can rotate freely in their places. The various forces which act upon these disks, as those derived from the insertion of the thread between them, the removal of the thread, the depression, of the push button 18 and the push of the 4spring 11 uponV the disk 10, cause slight rotations of these disks from time to time so that the thread is continually passing between new surfaces and consequently there is no tendency for the thread to wear a groove in the tensioning surfaces, as is the case where such surfaces are immovable with respect to the thread. It will be seen that the push button 18, the construction of which has been described, releases the tension when depressed, and also operates to maintain the thread in position and to prevent its accident-al disengagement from the tension. The push button 18 thus performs a double function.

Having'now described my invention, I claim:

1. In a tension for sewing machines, the combination of a barrel, a disk fitting' the bore of the barrel and held from lateral movement thereby, a second disk below the first, and fitting the bore of the barrel and guided vertically thereby, a thread being passed between the two disks, a spring' for pressing the second disk upward, and adjustable means beneath the said spring' for regulating the compression thereof, substantially as set forth.

2. In a tension for sewing machines, the combination of a pair of freely rotatable disks through which a thread is passed, a barrel wherein the disks are held and fitting the bore thereof to be held thereby from lateral movement, the said barrel being provided with a seinicircular slot in alinement with the space between the disks and a spring in the said barrel beneath the lower disk and pressing the lower disk upwardly, substantially as set forth.

3. In a tension for sewing machines, the combination of two freely rotatable disks between which a thread is passed, means for pressing said disks together and means passing through one of the disks and contacting with the other disk whereby the disks may be pressed apart to release the tension, and serving also to hold the thread in place between the disks to prevent its accidental removal, substantially as set forth.

4. In a tension for sewing machines, a barrel, a pair of tension members therein,

a spring in said barrel to force the tension members together, a rotatable disk beneath the said barrel and means whereby the rotation of the disk varies the pressure between the tensioning members, substantially as set forth. A Y

5. In a tension device for sewing machines, the combination of a barrel apertured for the passage of a thread, a pair of tension disks therein, aspring beneath said disks for pressing them together, a screw with an enlarged head beneath the said spring, means for preventing rotation of the screw, and a rotatable disk on said screw for raising and lowering the screw to vary the tension on the spring, substantially as set forth.

6. In atension device for sewing machines, the combination of a pair of tensionmembers, a barrel wherein the same are received and held against sidewise movement, a spring for pressing them together, and means located between an end of said barrel and the machine head and bearing upon said head and adapted to vary the pressure on the said spring, substantially as set forth.

7 In a tension device for sewing machines, the combination of two relatively movable tensioning disks between which a thread is passed, a barrel having a cylindrical bore adapted to receive said disks and hold the same from lateral movement, one of the disks being provided with an aperture and the other with an alining recess,

and a member passing through the aperture and entering the recess and provided with a slot in its end through which the thread is passed, substantially as set forth.

8. In a tension device for sewing machines, the combination of a barrel on the machine head and apertured for the passage of a thread, a pair of disks in said barrel and between which the thread is passed, a spring for pressing the disks together and means for placing the spring under tension comprising a screw and a disk having an internally threaded aperture for the passage of said screw and situated between the barrel and the lmachine head, substantially as set forth.

9. In a tension device for sewing machines, the combination of a barrel perforated for the passage of the thread, a pair of disks within said barrel and between which a thread is passed, one of saiddisks being provided with an aperture and the other with a recess in alinement with the said perforation, means for yieldably pressing the disks together and a push button passing through the perforation in the first named disk, and contacting with the bot-- tom of the recess in the second named disk and the shank thereof being of greater length than the combined depth of the aperture and recess so that when the button is depressed the pressure between the disks will be released and a spring for pressing the disks together, substantially as lset forth.

l0. In a tension device for sewing machines, the combination of two relatively movable tension disks, a` barrel having a cylindrical bore adapted to receive said disks and hold the same from lateral movement, one lof said disks being provided with an aperture and the other with an alining recess, a member passing through the aperture and entering the recess and contacting with the bottom of the latter and movable within the aperture and the recess, said member being provided with a central slot in its end for the passage of a thread and being shortened at one side of the slot and provided on the shortened side with a cam shaped surface, substantially as set forth.

1l. In a tension device for sewing machines, the combination of a barrel apertured for the passage of a thread and having an opening in its top, a pair of tension disks between which the thread is passed, one of said disks being provided with an aperture and the other with an alining recess, a push button passing through the aperture in the top of the barrel and having a portion of reduced diameter passing through the aperture in the rst disk and into the recess in the other disk and contacting with the disk at the bottom of the recess and provided with a slot in its end, the portion at one side of the slot being shortened and provided with a cam shaped surface, substantially as set forth.

12. In a tension device for sewing machines, the combination of a barrel apertured for the passage of a thread, a pair of tension disks within said barrel and between which the thread is passed, a spring in said barrel -for pressing the disks together, means passing through one of the disks and contacting with the other disk for preventing accidental removal of the thread and for releasing the tension, and means beneath the barrel and accessible from the outside thereof for varying the tension of the spring, substantially as set forth.

13. In a tension device for sewing machines, the combination of a barrel secured to the machine head with a space between its bottom and top of the head and apertured for the passage of a thread, a pair of tension disks in the said barrel and between which the thread is passed, a spring within the barrel for pressing the tension disks together, a rotatable disk within the space between the barrel and the machine head and means whereby the rotation of the last named disk will vary the pressure between the tension disks, substantially as set forth.

14. In a tension device for sewing niachines, the combination of a barrel secured to the machine head leaving a space between the barrel and head and the barrel being apertured for the passage of a thread, a pair of tension disks therein and between which the thread is passed, a spring for holding the disks together, a screw with an enlarged head upon which the spring rests, means on the machine head for preventinfT the rotation of the screw and an internally threaded disk on said screw and within the space between the barrel and the machine head whereby the rotation of the last named disk will move the screw longitudinally to vary the tension of the spring, substantially as set forth.

15. In a tension device for sewing machines, the combination of a barrel apertured for the passage of a thread, a pair of Copies of this patent may be obtained for ve cents each, by addressing the tension members in said barrel, a spring in said barrel, the barrel being provided with sidewise projecting lugs at its bottom and' the machine head being provided with upward extensions to support the said lugs and with a' recess therebetween whereby a space is left between the barrel and the machine head and means occupying the space between the said barrel and machine head for placing the spring under tension, substantially as set forth.

Signed at Newark, New Jersey, this 26th day of March, 1909.

n STEPHEN A. DAVIS. vWitnesses:

H. H. DYKE, JOHN M. OANFIELD.

Commissioner of Patents,

Washington, D. C. 

